Process of treating fluids, such as water and sewage.



I J. M. NEIL. PROCESS OF TREATING FLUIDS SUCH AS WATER AND SEWAGE. APPLICATION FILED MAR. 1, 1912.

1,045,096. Patented Nov. 19, 1912.

lV/TNESSES HVVE/YTOR UNITED. STATES PATENT or ricn.

JAMES MI'LLAR'NE IL, or NEW YORK, N. Y. i

PROCESS OF TREATING ILUTDS, SUCH AS WATER AND SEWAGE.

l Specification of letters Patent. Patented NOV. 19, 1912.

Application filed March 1, 1912. Serial missions.

To all. whom it may concerni- Be it known that I, JAMES MILLAR NEIL, of New York, in the county of New York and State of New York, have invented cerespecially sewage, a precipitant (such as a compound of calcium 'oxid, and calcium carbonate, or a'mixturepfsuch calcium compounds) has, been used to effect the precipitation of organic matter and f eign substances, etc., in the fluid; and hypochlorite I taut and essential factor is actions.

of calcium has been also used in connection therewith as a germicide. The precipitated matters resulting from the above treatment are of sucha natureas to render their separation from the liquid or Water adiflicult or tedious-and slowoperation, and it has heretofore been customary to effect this separation by meansof settling tanks, and sand or similar filtration beds,as oWin to the character of ,such precipitates t eir separation by mechanical filters has been proyen impractical. 'Owing principally to imperfect'precipitation of the organic matter, and the small percentage of bacteria left; but more especially to the length of time in which the precipitates are left in contact with the liquid undergoing treatrnent; secondary reactions occur which prevent the maximu'in purification being accomplished, and the bacteria is only held in check by use of an excess of germicide.

A purification process for fluids, suchas water or sewage, should efiectthe-thorough precipitation of all the or .anic and foreign matter therein, the compl to" destruction .of harmful bacteria; and produce a clear liquid, free from odor, etc. In'order to produce the above desired results, an importhat the separation of the liquid from the solid matter shouldbe rapidly effected in order to prevent the occurrence of any secondary re- Another feature of vthe purification of fluids is that the process or system used should be such as can be carried on continuously. v

I have discovered that by using an amount of precipitant (such as lime or cal cium oxid,) greatly in excess of what has heretofore been deemed and used as suiticient or necessary to effect the precipitation, the physical nature of the precipitates is changed; in-other words by using an excess amount of calcium oxid the organic and foreign matter in the fluid undergoing treat ment will be rendered more or less friable, porous or granular; and the clear liquid can then be effectually and economically separated from such precipitates by a 'me ch-anical filter; and because of the change inthe nature or composition of the solids produced by the use of the excess precipitant, a vastly greater quantity of clear liquid can be Withdrawn through such filter before its surface becomes coated, than would be possible if only the ordinary small amount of precipitant had been employed. I have furthermore foundthat by employing a suction filter the clear liquid can be withdrawn rapidly from such a mixture; and that When a coating forms upon the surface of such filter, (as it ultimately will do),'by temporarily stopping the suction and forcing Water or air back through the filter such coating can be thrown off the filter back into the mixture; then the suction operation can be ,at once resumed to Withdraw more clear liquid from the mixture, so that instead of having to remove the filter each time it becomes coated it can be quickly cleared by a reversed current therethrough, as described; and in this Way by my-process I am enabled to treat liquid substantially continuously and to practically effect the rapid and almost continuous separation of the clear liquid from the solids in the fluid undergoing treatment. The successful operation of my process depending upon the employment of'an excess precipi tent; and the intermittent throwingofi' of the coating on the filter as above described. By this invention fluids, such as water and sewage, can be purified and. rendered clear and odorless, free from harmful bacteria, and foreign and organic matter; and this result can be obtained in an efficient rapid and economical manner, and my process can be performed continuously if so desired.

In the practical utilization of my invention, I preferably introduce the fluid, such as water or sewage, to be treated into a tank or other receptacle; first passing the fluid 5 preferably through screens to remove flo atage and large foreign bodies therefrom; then I mix with the fluid in the tank or receptacle a quantity of a precipitant, (such'as lime, calcium hydrate, o-r carbonate, caustic soda, and the like,) exceeding one hundred grains per gallon of fluid in the tank and agitate the mixture.

Instead of using merely such an amount of the precipitant as has heretofore and now been considered necessary to cause precipi tation of the foreign and organic matter in the fluid I use a large amount of such precipitant, 1n excess of that required to insure separation of the precipitated and organic matter in the fluid, from the liquid and over one hundred grains per gallon of fluid in the tank; and by using such excess of precipitant its effect upon the fluid is practically instantaneous while the mixture is in agitation.

In treating age, by my process the use, for example, of

an excess supply of calcium carbonate in conjunction with calcium hydrate and any other desired c emical, (such as alumina in various forms, etc., and hypochlorite of lime, or. s0d-a,) to destroy bacteria; produces a rapid, efi'icient and complete precipitation of the solids and foreign matters from the fluid, and enables the clear liquid to be at once separated from the mixtureby mechanical filtration.

I prefer to placein the tank or receptacle.

at the commencement of the operation such a quantity of the precipitant that when the tank or receptacle is full there will be present in the mixture therein about three parts fluid to one part of the precipitant, such .as

. lime, calcium carbonate, etc. I havefound that these proportions give excellent results,

but I do not limit myself thereto.

' As the clear liquid is withdrawn from the tank or receptacle through the filter, additionalfluid may be admitted into the tank so or receptacle and additional precipitant may be added asit becomes depleted so as. to

. maintain; a large excess supply thereof.

. Y The contents of, the tank Olf receptacle should be kept in a state of agitation by any sultable means; for instance by blowing air or steam', therethrough, or by mechanical st1rrers,etc..

At a point preferably remote from the intank, I'place a mechanical filter which may be of any suitable construction; butI preferably use a hollow filter having walls of any suitable material permeable to clear llquid but not permeable to solids, and the 5 interior of such filter is connected with a fluids, such as water or sewof the fi-lter,-,by preventing the formation let to the tank or receptacle but Within the suitable pumping or suction, apparatus by means of which the clear liquid can be rapidly withdrawn from the tank or receptacle through thefil-ter. The withdrawal of the clear liquid from the agitated mixture in the tank through the suction filter tends to draw toward and against the filter surfaces any matter in suspension in-the mixture in the tank or receptacle, which matter ultimately forms a coating upon the surfaces of the filter.- In this connection the use of such excess of precipitant is of importance in enabling the filtering operation 'to be performed efli-. ciently and practically continuously; for I have found that the -successful operation of mechanical filters on fluids, such as .water i that the resistance to the suction should be practically uniform throughout the filter surfaces. For example, when using suction filters for fluids, such as water or sewage, large particles of matter drawn against the filter surface ordinarily affect the uniformity of the suction and cause imperfect operation of a uniformly resistant or permeable cake or coat on the surfaces thereof; but as a result of the presence of an excess of calcium in the mixture in the tank or receptacle, in my process; should any such large mass be drawn against the surface-of the filter, such mass would be quickly coated with a calcium deposit untilthe uniformity of suction. is substantially restored. Thus the use of such excess of precipitant insures that the coating on the filter will be always substantially uniform in permeability throughout theentire. surf-ace of-the filter.

In the accompanying drawing ,1 have illustrated, diagrammatically, an apparatus for carrying. my process into effect.

In said drawing, '2 represents an open tank into which the fluid to be treated is preferably continuously admitted through a p1pe or conduit 1. An excess quantity of precipitant'is maintained in the tank, as stated and the mixture may be agitated in the discharged from the ump. 4 into the upper portion of the tank t rough a pipe 5.

6 designates a hollow suction filter having permeable wallawhich may be connected by means of a pipe 7 to a suction ump 8, by which the clear liquid can be wit drawn from the tank and discharged through a pipe9 atany suitable point. The pump 8 is preferably of such; construction that 1t can be reversed so as to momentarily force clear liquid back through the pipe 7 and ing the surface of the filter; and then the suction operation can be immediately resumed as described.

. In water sometimes, and in sewage always, there is present more or less oil, grease, etc, which when brought into contact. with the surface of the filtering medium tends to form a film thereon and retard the process of filtration; but in my process, owing to the excess of alkali present, such Loils and greases will be saponified; or if they are in an unsaponifiable condition, so comminuted, divided and commingled with the precipitant and fine particles of solids in the mixturetha-t they will not tion of the filter. I The addition of such ex: cess ofa. substance, such as finely subdivided calcium carbonate, finely divided, or flocculent silica, or similar substances,to

the fluid undergoing treatment also insures.

the production or formation of a substantially uniform coating 'or layer of material on the surface of the suction filter; as such material. acts as a hinder or collector of the suspendedmatter in the fluid and changes them in such manner as will allow of the rapld separation of the liquid-constituents of the mixture herefrom.

The withdraw of the clear liquid from the agitated mixture in the tank may be continued until the solids form acoat'ing on the outer surfaces of the filter of such thickness as to lower theefliciency of the filter below the desired point '(which will beindicated by the vacuum gage) then the suction should be temporarily stopped and liquid or air forced back through the filter,

thereby throwing off the solids adhering to the outer surfaces of t-hefilter, which drop back into the mixture in the tank or receptacle; The suction operation may then-be resumed and clear liquid withdrawn from the mixture until the filter is again coated;

then it may be again cleared by temporarily- I forcing liquid or air back through the filter as above stated. By thus intermitting the suction operations by throwing off the coating on the filter, I amable to continue the withdrawal of clear liquid from the tank or K receptacle indefinitely, and practically .con-

) tinuously; as the time required to reverse the current and throw off the coating on the filter surfaces is very short. I preferably contlnuesuch filtering operation until such amass of solids has accumulated in the tank, or receptacle, as to render it desirable to remove same therefrom, which may be done in any desired way. 1

I The intermittent throwing an of the solids adhering to the filteris important in the practical economical utilization of my pr cess, as by this means the filter leaves can prevent the opera always be maintained at their-highest efficiency.

My process allows of the continuous treatment of water or sewage, as the clear liquid is withdrawn immediately from the agitated mixture as soon as the solids have been precipitated in the liquid. Another important advantage of using such excess of precipitant is that the fluids, such as water or sewage, can be treated by my process .in open tanks, for the obnoxious odors are at once killed, and a harmless and clear effluent is produced, and owing to the immediate and complete separation of-the liquid from the organic and other foreign matter in the mix= ture no secondary. reactions occur in the separated liquid.

' Thesolids may be conveniently removed from the tank or receptacle by withdrawing clear liquid through the filter until its surfaces are thickly coated with the solids.

flhe coated filter may then be withdrawn from the tank or receptacle to a suitable point, continuing the suction if necessary to prevent the cakeor coating dropping from the surfaces; then the suction may be stopped and the coating discharged from the filter surfaces into a suitable receiver by sluicing, washing or scraping the coating off or discharging it by means of a reversed ation can be repeated until as much of the solids in the tank have been removed as is desired: then resumed. v

It is not desirable to remove the filter from the tank every time it becomes coated, although this might be done, as such removal requires comparatively considerable time; which time can be saved and utilized in my process for the filtering operation by simply reversing the current through the filter to throw the coating thereon back into the tank or receptacle as above described.

If desired a series of tanks or receptacles may be employed, and when the mixture in one tank orreceptacle has become so thick that it is desired to remove the solids, the supply of fluid to such tank or receptacle might be stopped ,until the solids are re-' moved therefrom; while the, filtering oper, tion is continued in the other tanks or receptacles.

I have also discovered that the efiiciency of the hypochlorite used as a germicide is greatly increased in my process wherein an excess of calcium is used, and that superior results are obtained in my. process by the use of a less quantity of germicide.

. Another feature of my process is that through the continuous agitation and drawing on and throwing off of-the solid matter on the filter-in the tank or receptacle such matter becomes thoroughly commingled and the filtering operation can be comminuted, and the precipitated; and other foreign matter originally in the water or sewage when utimately separated from the tank will be found to be finely divided and greases which may have been saponified by 1 the alkali used; and such oils, greases, etc., recovered by any of the well known methods, .and the residue used as a fertilizer. The solids however may also be incinerated to destroy the organic matter therein and regencrate the calcium compounds, which may then be reused in the tank if so desired.

, What Iclaim is:

ing-fluids', such asuwater and sewage, consistingin-introducingfluids into a tank and maintaining in the tank a quantity of precipitant exceeding 100 grains to a gallon'of fluid; agitating the fluid with such precipitant to effect precipitation of the foreign and organic matters contained in the fluid, and simultaneously withdrawing from the mixture while in-agitation the clear liquid through a suitable filter.

2. The herein described process of treating fluidssuch as water and sewage, consist- The separated solids could also be 1. The herein described process of treat-- ing in mixing the fluidin a tank with aquantity of a precipitant in excess of the amount necessary to obtain precipitation of the foreign and organic matters contained in the fluid, the quantity of precipitant in the mixture exceeding 100 grains to a gallon of fluid; agitating such mixture in the tank; and continually withdrawing vfrom such agitated mixture the clear liquid through a suitable filter in the tank.

3. The hereindescribed process 'of treat ing fluids, such as water or sewage; consisting in. introducing the fluid into a tank;

mixing therewith an excess quantity of a suitable precipitant; the, quantity of precipitant in the tank exceeding 100 grains per gallon of the fluid in the tank; agitating the mixture in the tank; and simultaneously withdrawing clear fluid .from the mixture by suction through a suitable filter located in the tank, while the mixture is in agitat-ion, until such filter is coated; then quickly clearing the filter and continuing the opera,-

tion.

In testimony that I claim the foregoing L as my own, I aflix my signature in presence of two wltnesses.

JAMES MILLAR EIL:

- Witnesses: I

JAMES R. MANSFIELD L. E. WITHAM. 

